Sacoolas was charged with causing the 19-year-old's death by dangerous driving in December after he was killed outside a US military base in Northamptonshire on August 27.

Charlotte Charles, the mother of Harry Dunn. (PA)

Police in Britain have issued an international wanted notice for Sacoolas, 42, and an extradition request submitted by the Home Office for her was rejected by US secretary of state Mike Pompeo in January.

But Ms Charles said she hopes the UK government will keep fighting on her behalf, despite Mr Pompeo saying the January ruling was “final”.

"We don't want any problems with the US Government. But we can see that the US Government is behaving like a bully,” she said.

"It will be a road to ruin if we back down as a country now and we have to stand up to them.

"I agree with calls that no-one should be extradited until the US Government agrees to play by the rules, starting with sending Anne Sacoolas back.

"She did not have diplomatic immunity."

The row over Sacoolas flared up once again this week after it emerged Home Secretary Priti Patel approved the extradition of Jabir Motiwala, 53, and Colin Wilkinson, 54, to the US from Hull last month.

Acting on behalf of Mr Dunn's parents, spokesman Radd Seiger added: "Arrangements for sending wanted people across the Atlantic are hopelessly weighted in favour of the Americans.

"As we have seen in the case of Anne Sacoolas, the American Government didn't even bother to go through the motions of putting the case through the legal and court system.